Turbine installation

ABSTRACT

A turbine installation, especially a gas turbine installation, includes foot plates of the guide blades of adjacent turbine stages being interconnected with a clip-type sealing element on their rear sides facing away from the gas area. This provides a simple seal between adjacent foot plates which is effective regardless of the thermal expansion of the foot plates. The clip-type sealing element is also suitable for sealing the tiles of a combustor of the turbine installation together.

This application is the national phase under 35 U.S.C. §371 of PCTInternational Application No. PCT/EP01/02094 which has an Internationalfiling date of Feb. 23, 2001, which designed the United States ofAmerica and which claims priority on European Patent Application numberEP 00104346.2 filed Mar. 2, 2000, the entire contents of which arehereby incorporated herein by reference.

FIELD OF THE INVENTION

The invention generally relates to a turbine installation, in particulara gas turbine installation.

By a gas turbine installation is meant hereafter an installation whichincludes a combustion chamber and a turbine located downstream of thecombustion chamber and designated as a gas turbine.

BACKGROUND OF THE INVENTION

In a combustion chamber of a gas turbine installation, a fuel gas isburnt in a gas space, and the hot gas generated at the same time issupplied to the turbine and flows through the latter. The flow path ofthe hot gas through the turbine is likewise designated hereafter as thegas space. The turbine has stationary guide vanes, which extend radiallyfrom outside into the gas space, and moving blades which are mounted ona shaft designated as a rotor and which extend radially outward from therotor. As seen in the longitudinal direction of the turbine, the guidevanes and the moving blades engage one into the other in a tooth-likemanner.

The turbine, as a rule, has a plurality of turbine stages, with a guidevane ring being arranged in each stage. Thus, a plurality of the guidevanes are arranged next to one another in the circumferential directionof the turbine. The individual guide vane rings are arrangedsuccessively in the axial direction.

Both at the combustion chamber and at the turbine, the gas space isconventionally lined with plate elements. At the combustion chamber,these are tiles, and at the turbine, the plate elements are formed bywhat are known as foot plates of the individual guide vanes.

The gas region of the combustion chamber and of the turbine is to be asleak-tight as possible. The aim is therefore to have insignificantleakage losses between the individual plate elements. In particular,leakage losses between two turbine stages are to be prevented.

As a result of the high temperature spans in the gas space, there is theproblem that a seal has to absorb and bridge expansions of theindividual plate elements, without the seal being appreciably impaired.This problem is aggravated by the fact that neither the tiles nor thefoot plates of the guide vanes are fastened at their edge regions toadjacent plate elements, so that the plate edges are to a greater orlesser extent free and undergo bending as a result of thermal expansion.The tiles, for example, are, as a rule, fastened in their center andbend approximately spherically under thermal load. A seal must thereforeallow both axial and radial movability, also because the combustionchamber and the turbine are designed conically in the axial direction.

In a conventional seal, the foot plates are provided in the region ofthe turbine with a groove on their end face, a sealing sheet beinginserted into the grooves of two foot plates of guide vanes of adjacentturbine stages. Where the end-face grooves are concerned, the axial andradial movability of the foot plates is achieved in that the grooveshave oblique side walls. However, grooves of this kind are highlycomplicated in production terms. Moreover, a seal of this kind isrelatively leaky, since a varyingly rapid thermal expansion behavior ofthe foot plates and of what is known as the turbine guide vane carrierto which they are fastened must be taken into account.

To be precise, when the turbine is started up, the foot plates expandmore rapidly, so that a leakage gap between the foot plates is initiallyclosed. The leakage gap opens again when the turbine guide vane carrierhas expanded according to the temperature.

With regard to the tiles in the combustion chamber, there isadditionally the problem that, because they bend spherically, such asealing sheet is sometimes subjected to shearing load until it fails.

SUMMARY OF THE INVENTION

An object on which an embodiment of the invention is based, is to makeit possible to have a seal which overcomes at least one of thedisadvantages described. The object may be achieved, according to anembodiment of the invention, by a turbine installation, in particular agas turbine installation, with a gas space which is outwardly delimitedvia plate elements contiguous to one another. A sealing element isassigned in each case to plate elements adjacent to one another andconnecting these to one another in a staple-like manner on their rearsides facing away from the gas space.

An advantage is seen in the staple-like configuration of the sealingelement. The sealing element thus spans the two plate elements. Underthermal expansions, the sealing element follows the plate elements,without opening up a gap. The seal produced by the sealing element istherefore largely unaffected by thermal expansions.

In order to ensure as good a seal as possible, even under all-roundthermal expansions, the sealing element preferably allows a movabilityof the plate elements both in the axial and in the radial direction. Thesealing element may therefore be designed, in particular, to be elasticboth in the axial and in the radial direction. By axial direction, whatis meant is an expansion in the longitudinal direction of the turbineinstallation and by radial direction, it means an expansionperpendicular to the longitudinal axis.

Preferably, the sealing element has two limbs which engage in each caseinto a groove of plate elements adjacent to one another. This makes itpossible to have a fastening of the sealing elements which is simple toimplement in production terms.

Preferably, the groove extends from the rear side of the respectiveplate element into the latter, essentially radially. The limbs thereforeproject radially outward from the grooves. This configuration of thegroove allows simple production and, in particular, high accuracy, forexample by grinding or erosion. An advantage of the arrangement on therear side is to be seen in that the groove does not have to be of aspecial shape with regard to the problem of thermal expansions. Thegroove and sealing element can therefore be adapted very accurately toone another, so that very small leakage gaps are achieved.

In order to make it possible to have a simple procedure for mounting theplate elements in the turbine installation, the sealing element ispreferably of multipart construction.

In this case, preferably, the limbs of the multipart sealing elementoverlap one another over a common circumferential length. Thiscircumferential length is in this case dimensioned sufficiently largeessentially to avoid leakages.

In a preferred embodiment, the sealing element is of U-shaped design,this being simple to implement both in production terms and in assemblyterms.

In order to achieve a high expandability of the sealing element, thelatter has a wavy structure in the manner of a concertina in order toabsorb expansions.

Expediently, the sealing element has this wavy structure in a pluralityof directions, so that it can absorb expansions in different directions.In particular, the sealing element has a configuration in the form of adouble S.

In a preferred embodiment, the sealing element is arranged betweenadjacent tiles of a combustion chamber. Reliable sealing between thetiles is consequently achieved, even when these bend spherically as aresult of thermal load.

According to a particularly preferred embodiment, the sealing element isarranged between the foot plates of adjacent guide vanes of a turbine,specifically, in particular, between the foot plates of guide vanes ofadjacent turbine stages.

The individual foot plates are accordingly connected to one another inthe axial or the longitudinal direction of the turbine via staple-likesealing elements.

In order to achieve simple mounting of the plate elements, in particularof the foot plates, and at the same time good sealing of the plateelements both in the circumferential direction and in the axialdirection between adjacent turbine stages, preferably, the staple-likesealing element described is provided for sealing in the axial directionand a further sealing element is provided for sealing in thecircumferential direction. Depending on the direction, therefore, and inparticular for assembly reasons, differently designed sealing elementsare used.

The further sealing element in this case preferably has a receptionregion, into which the plate elements extend. In particular, the sealingelement is designed with an H-shaped cross section. The fundamental ideaof this configuration is to be seen in the reversal of a conventionalsealing principle, in which a sealing sheet is introduced intocorresponding end-face grooves of the foot plates. To be precise, this,as a rule, necessitates a reinforcement of the edge of the foot platesin the groove region. This presents problems with regard to an effectivecooling of the foot plates, since, on account of the different materialthicknesses, a uniform cooling can be implemented only with difficultyand thermal stresses may occur. In this case, in a reversal of thissealing principle, the sealing sheet is not inserted into the footplates but, instead, the foot plates are introduced into the sealingelement. This avoids the need for a reinforcement of the edge region ofthe foot plate. Coolability is thus simplified and the foot plate iscooled homogeneously in all regions, so that no thermal stresses occur.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention are explained in more detailhereafter with reference to the drawings, in which, in each case in aroughly simplified illustration,

FIG. 1 shows a turbine installation with combustion chamber and turbine,

FIGS. 2 and 3 show different conventional seal variants,

FIG. 4 shows the seal variant according to the invention,

FIGS. 5-7 show different variants of a seal element, and

FIG. 8 shows a seal provided, in particular, for plate elements arrangednext to one another in the circumferential direction.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to FIG. 1, a turbine installation 2, in particular a gasturbine installation of a turbo set for a power station for energygeneration, comprises a combustion chamber 4 and a turbine 6 which isarranged downstream of the combustion chamber 4 in the longitudinal oraxial direction 8 of the turbine installation 2. Both the combustionchamber 4 and the turbine 6 are illustrated, cut away, in a part region.It is consequently possible to look into the gas space 10 of thecombustion chamber 4 and into the gas space 12 of the turbine 6.

During operation, the combustion chamber 4 is supplied via a gas supply14 with a fuel gas BG which is burnt in the gas space 10 of thecombustion chamber 4 and forms a hot gas HG. The gas space 10 is linedwith a multiplicity of tiles 13 designed as plate elements. The hot gasHG flows through the turbine 6 and leaves the latter as cold gas KG viaa gas discharge line 16. The hot gas HG is guided in the turbine 6 viaguide vanes 18 and moving blades 20. In this case, a shaft 22, on whichthe moving blades 20 are arranged, is driven. The shaft 22 is connectedto a generator 24.

The moving blades 20 extend radially outward from the shaft 22. Theguide vanes 18 have a foot plate 32 and a vane leaf 21 fastened to thelatter. The guide vanes 18 are in each case fastened outwardly to theturbine 6 on what is known as a guide vane carrier 26 via their footplates 32 and extend radially into the gas space 12. As seen in thelongitudinal direction 8, the guide vanes 18 and the moving blades 20engage one into the other in a tooth-like manner. A plurality of movingblades 20 and of guide vanes 18 are in this case combined to form aring, each guide vane ring representing a turbine stage. In theexemplary embodiment of FIG. 1, the second turbine stage 28 and thethird turbine stage 30 are illustrated by way of example.

The foot plates 32 of the individual guide vanes 18, like the tiles 13,are designed as plate elements which are contiguous to one another bothin the axial direction 8 and in the circumferential direction 33 of theturbine 6 and which delimit the gas space 12. The location marked by acircle in FIG. 1 is illustrated, enlarged, in FIGS. 2 to 4. The seal,described with regard to these figures, between two foot plates 32which, in particular, are arranged next to one another in thelongitudinal direction 8 can also be transferred accordingly to form aseal for the tiles 13 of the combustion chamber 4.

According to FIG. 2, in a conventional variant illustrated here, sealingis carried out, without a special sealing element, solely by virtue ofan overlap of foot plates 32 adjacent to one another. The two footplates 32 have a step-shaped design in the overlap region. Under thermalstress and the associated expansion, the two foot plates 32 aredisplaced relative to one another in a movement superposed in thelongitudinal direction 8 and in the radial direction 36. The leakage gap38 formed between the two foot plates 32 varies as a result. The sealingaction thus depends decisively on the expansion behavior of the footplates 32.

The foot plates 32 according to FIGS. 2 to 4, each have, on their rearside 39 facing away from the gas space 12, a hooking element 40 viawhich the foot plates 32 are held on the guide vane carrier 26 (cf. FIG.1). Each foot plate 32 in this case typically has two hooking elements40 which are configured differently and allow movability both in theaxial direction 8 and in the radial direction 36.

According to FIG. 3, a further conventional sealing arrangement has asealing sheet 42 which is inserted into grooves 44 in the adjacent footplates 32. The grooves 44 are in this case worked into the end faces 46of the foot plates 32. They have an opening angle a of approximately15°, in order to allow a movability of the foot plates 32 in the radialdirection 36. In this embodiment, too, there is formed between thesealing sheet 42 and the foot plates 32 a leakage gap 38 which varieswith expansion as a result of the thermal load. This variation iscaused, inter alia, by the fact that the foot plates 32 expand morerapidly than the guide vane carrier 36 to which they are fastened.

In particular, the problems of the temperature dependence of the leakagegap 38 do not arise in the novel configuration according to FIG. 4.According to this, grooves 44, which extend essentially radially intothe foot plates 32, are worked into the rear side 39 of the two footplates 32 in the region in which the latter are contiguous to oneanother. It must be stressed that the grooves 44 according to FIG. 4have parallel side walls 50, in contrast to those of FIG. 3. This allowsa particularly simple production of the grooves 44.

A U-shaped sealing element 42A is introduced with its two limbs 52 intothe grooves 44 and, in particular, is fastened. Fastening is carriedout, for example, by means of a clamping action or else by welding. Thesealing element 42A is produced, in particular, as a sheet-metalelement. Its limbs 52 extend outward, essentially in the radialdirection, so that the arc 54 connecting the two limbs 52 is at adistance from the rear side 39. This elongate design makes it possiblefor the sealing element 42A to have an elastic behavior, that is to sayit follows the thermal expansions of the foot plates 32. The thermalmovability of the foot plates 32 is thus ensured by the bendable orexpandable sealing element 42A. Movability is therefore independent ofthe special configuration of the grooves 44, so that these can beadapted with a highly accurate fit to the limbs 52. Between the limbs 52and the grooves 44, therefore, no or only a very small leakage gap 38 isformed, which is independent of the thermal stress on the foot plates32.

Alternative embodiments of the sealing element 42A are illustrated byway of example in FIGS. 5 to 7. According to FIG. 5, a sealing element42B is formed from two separate limbs 52 which each have an arc 54 andoverlap one another over a circumferential length L. The multipartdesign of the sealing element B simplifies mounting, since, for example,individual limbs 52 can simply be fastened into the correspondinggrooves 44 of the respective foot plates 32, even before the mounting ofthe guide vanes 18, and the foot plates can subsequently be attached tothe guide vane carrier 26. The common circumferential length L selectedis in this case as large as possible, in order to keep the leakage gap38 formed between them small for all thermal and operating states.

In an alternative multipart design of a sealing element 42C according toFIG. 6, only one limb 52A is provided with an arc 54, whereas the secondlimb 52B is a straight sheet-metal piece. In the multipart sealingelements 42B, 42C it is advantageous if the individual limbs 52 arepressed against one another in the mounted state and, for example, havesome spring tension.

According to FIG. 7, a sealing element 42D is provided with a wavystructure 58 which replaces the simply configured arc 54 according toFIGS. 4 to 6. This wavy structure 58 extends preferably in a pluralityof directions, in particular in the two directions parallel to the footplates 32. In addition, the limbs 52, too, may be wavy. The sealingelement 42D is thus designed in the manner of a concertina and makes itpossible to absorb even high thermal expansions in a plurality ofdirections, without the leakage gap 38 being enlarged.

The sealing elements 42A to 42D preferably connect the foot plates 32 ofguide vanes 18 of adjacent turbine stages 28, 30 for assembly reasons.In order to achieve a good and simply mountable seal even in thecircumferential direction 33, a further sealing element 60 is providedfor guide vanes 18 of a guide vane ring which are adjacent to oneanother in the circumferential direction 33.

According to FIG. 8, the further sealing element 60 is preferablydesigned with an H-shaped cross section and has two longitudinal limbs62 which are connected to one another via a transverse limb 64. Betweenthe two longitudinal limbs 62 are formed two reception regions 65 whichare separated from the transverse limb 64 and into which the foot plates32 extend. The side edges 66 of the foot plates 32 are bent away outwardfrom the gas space 12 approximately perpendicularly and fit snuglyagainst the transverse limb 64.

This configuration with the reception regions 65 for the foot plates 32advantageously makes it possible to have a material thickness which ishomogeneous over the entire foot plate 32, so that uniform cooling ofthe foot plate 32 is ensured and thermal stresses in the foot plate 32do not occur.

To cool the foot plates 32, in particular, a closed cooling system 68, adetail of which is illustrated in FIG. 8, is provided, with steam as thecoolant. This closed cooling system 68 has an inflow duct 70 and areturn-flow duct 72. The inflow duct 70 is formed between an outer guidesheet 74 and a baffle sheet 76, which is arranged between the guidesheet 74 and the foot plate 32. The baffle sheet 76 has flow orifices 78which are designed in the manner of nozzles, so that the coolantsupplied via the inflow duct 70 flows over into the return-flow duct 72along the arrows illustrated. By virtue of the nozzle-like operation ofthe flow orifices 78, the coolant is guided at high velocity against therear side 80 of the foot plate 32, so that effective heat transmissionbetween the coolant and the foot plate 32 is implemented.

The baffle sheet 76 is supported against the foot plate 32 and kept at adistance from the latter via supporting elements 82, for example in theform of weld spots or welded webs. The baffle sheet 70 is directlyfastened, in particular welded, to the side edge 66 of the foot plate 32and the guide sheet 68 is fastened to the baffle sheet 70.

A flow path 84 in the form of a leakage gap is formed between thefurther sealing element 60 and at least one of the foot plates 32, sothat, for example, air from the outside space 86 facing away from thegas space 12 can flow via the flow path 84 into the gas space 12 andconsequently cools the seal region, that is to say the sealing element60 and the side edges 66.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

What is claimed is:
 1. A turbine installation, comprising: plateelements, outwardly delimiting a gas space; a sealing element, includingtwo limbs assigned to plate elements adjacent to one another andconnecting these to one another in a staple-like manner on their rearsides facing away from the gas space, wherein the sealing elementengages a respective limb into a respective groove, arranged in plateelements adjacent to one another, wherein the groove extends from therear side of the respective plate element into the latter.
 2. Theturbine installation as claimed in claim 1, wherein the sealing elementpermits movability of the plate elements, both in the axial directionand in the radial direction.
 3. The turbine installation as claimed inclaim 2, wherein the sealing element is of multipart construction. 4.The turbine installation as claimed in claim 3, wherein the two limbs ofthe multipart sealing element overlap one another over a commoncircumferential length.
 5. The turbine installation as claimed in claim2, wherein the sealing element is of U-shaped design.
 6. The turbineinstallation as claimed in claim 2, wherein the sealing element includesa wavy structure in the manner of a concertina, in order to absorbexpansions.
 7. The turbine installation as claimed in claim 6, whereinthe sealing element includes the wavy structure in a plurality ofdirections.
 8. The turbine installation as claimed in claim 2, whereinthe sealing element is arranged between foot plates of adjacent guidevanes of a turbine.
 9. The turbine installation as claimed in claim 1,wherein the sealing element is of U-shaped design.
 10. The turbineinstallation as claimed in claim 1, wherein the sealing element isarranged between adjacent tiles of a combustion chamber.
 11. The turbineinstallation as claimed in claim 1, wherein the groove extendsessentially radially.
 12. A turbine installation, comprising: plateelements, outwardly delimiting a gas space; a sealing element, includingtwo limbs assigned to plate elements adjacent to one another andconnecting these to one another in a staple-like manner on their rearsides facing away from the gas space, wherein the sealing elementengages a respective limb into a respective groove, arranged in plateelements adjacent to one another, wherein the sealing element is ofmultipart construction.
 13. The turbine installation as claimed in claim12, wherein the two limbs of the multipart sealing element overlap oneanother over a common circumferential length.
 14. The turbineinstallation of claim 12, wherein the turbine installation is a gasturbine installation.
 15. A turbine installation, comprising: plateelements, outwardly delimiting a gas space; a sealing element, includingtwo limbs assigned to plate elements adjacent to one another andconnecting these to one another in a staple-like manner on their rearsides facing away from the gas space, wherein the sealing elementengages a respective limb into a respective groove, arranged in plateelements adjacent to one another, wherein the sealing element includes awavy structure in the manner of a concertina, in order to absorbexpansions.
 16. The turbine installation as claimed in claim 15, whereinthe sealing element includes the wavy structure in a plurality ofdirections.
 17. A turbine installation, comprising: plate elements,outwardly delimiting a gas space; a sealing element, including two limbsassigned to plate elements adjacent to one another and connecting theseto one another in a staple-like manner on their rear sides facing awayfrom the gas space, wherein the sealing element engages a respectivelimb into a respective groove, arranged in plate elements adjacent toone another, wherein the sealing element is arranged between foot platesof adjacent guide vanes of a turbine.
 18. A turbine installation,comprising: plate elements, outwardly delimiting a gas space; a sealingelement, including two limbs assigned to plate elements adjacent to oneanother and connecting these to one another in a staple-like manner ontheir rear sides facing away from the gas space, wherein the sealingelement engages a respective limb into a respective groove, arranged inplate elements adjacent to one another, wherein the sealing element isarranged between axially adjacent plate elements.
 19. The turbineinstallation as claimed in claim 18, further comprising: a furthersealing element with a reception region, into which the plate elementsextend, provided between plate elements adjacent to one another in thecircumferential direction.
 20. The turbine installation as claimed inclaim 18, wherein a further sealing element is provided between footplates of guide vanes.
 21. A turbine installation, comprising: plateelements, outwardly delimiting a gas space; a sealing element, includingtwo limbs assigned to plate elements adjacent to one another andconnecting these to one another in a staple-like manner on their rearsides facing away from the gas space, wherein the sealing elementengages a respective limb into a respective groove, arranged in plateelements adjacent to one another, wherein the sealing element isarranged between foot plates of guide vanes of turbine stages adjacentto one another.
 22. The turbine installation as claimed in claim 21,further comprising: a further sealing element with a reception region,into which the plate elements extend, provided between plate elementsadjacent to one another in the circumferential direction.
 23. Theturbine installation as claimed in claim 22, wherein the further sealingelement is provided between foot plates of guide vanes.